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Leicester Warwick Medical School

Leicester Warwick Medical School. Neoplasia 1 What is a Tumour? Professor Rosemary A Walker raw14@le.ac.uk Department of Pathology. WHAT IS A TUMOUR?. a swelling inflammatory – abscess neoplasm - growth. NEOPLASM.

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Leicester Warwick Medical School

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  1. Leicester Warwick Medical School Neoplasia 1 What is a Tumour? Professor Rosemary A Walker raw14@le.ac.uk Department of Pathology

  2. WHAT IS A TUMOUR? a swelling inflammatory – abscess neoplasm - growth

  3. NEOPLASM • Abnormal growth of cells which persists after initiating stimulus has been removed • Cell growth has escaped from normal regulatory mechanisms • Benign • Malignant

  4. BENIGN NEOPLASM Cells grow as a compact mass and remain at their site of origin

  5. MALIGNANT NEOPLASM Growth of cells is uncontrolled Cells can spread into surrounding tissue and spread to distant sites Cancer = a malignant growth

  6. HOW DO TUMOURS DEVELOP? • There has to be a change to DNA • The change must cause an alteration in cell growth and behaviour • The change must be non-lethal and be passed onto daughter cells

  7. HOW DO TUMOURS DEVELOP? • Alteration is to more than one gene • Genes concerned are oncogenes/tumour suppressor genes • Sequence of gene alterations from normal to benign to malignant • Intrinsic and extrinsic / inheritance and environment key factors

  8. A A A A A A B B B B B B CLONALITY Alterations in genes regulating growth and behaviour occur in every cell – monoclonal population Evidence from studying G6PD In heterozygotes cells contain either G6PD A or G6PD B, but tumours in those people consist of cells that all have the same enzyme OR NORMAL CANCER

  9. HOW DO NEOPLASTIC CELLS DIFFER FROM NORMAL CELLS? Alterations in growth control • proliferation • cell death • factors regulating growth and response Alterations in cellular interactions • cell-cell • cell-stroma

  10. GROWTH CONTROL • Increased cell proliferation more cells enter cell cycle cell cycle “speeded up” • Cells have changed life span • Alterations in cell death-decreased apoptosis • Modification of cell metabolism • Angiogenesis

  11. GROWTH CONTROL • Increased or decreased growth factor receptors or altered receptors • Synthesis of growth factors – autocrine or paracrine effect • Excess/modified growth control proteins e.g. oncoproteins

  12. Autocrine Increased DNA synthesis and proliferation Growth factor receptor = Growth factor Paracrine

  13. CELLULAR INTERACTIONS Cell-cell interactions Cell-stromal interactions with basement membrane Important for cell and tissue differentiation, embryogenesis, growth regulation

  14. Desmosomes Ordered Cytoskeleton Basement membrane Cell receptors Disorganised Cytoskeleton Loss of cell receptors

  15. DIFFERENCES BETWEEN BENIGN AND MALIGNANT NEOPLASMS • Size • Growth characteristics • Vascularity/necrosis • Function • Invasion/metastasis

  16. BENIGN Nuclear variation in size and shape minimal Diploid Low mitotic count, normal mitosis Retention of specialisation MALIGNANT Nuclear variation in size and shape minimal to marked, often variable Range of ploidy Low to high mitotic count, abnormal mitosis Loss of specialisation DIFFERENCES BETWEEN BENIGN AND MALIGNANT NEOPLASMS

  17. BENIGN Structural differentiation retained Organised Functional differentiation usually MALIGNANT Structural differentiation shows wide range of changes Not organised Functional differentiation often lost DIFFERENCES BETWEEN BENIGN AND MALIGNANT NEOPLASMS

  18. DYSPLASIA • Premalignant condition • Increased cell growth • Cellular atypia • Altered differentiation • Can range from mild to severe • Sites -cervix -bladder -stomach

  19. IN-SITU MALIGNANCY Epithelial neoplasm with features of malignancy • altered cell growth • cytological atypia • altered differentiation BUT-no invasion through basement membrane

  20. POSSIBLE EVENTS Benign Benign Benign Dysplasia Benign Dysplasia In-situ Benign Dysplasia In-situ Invasive Dysplasia In-situ Invasive In-situ Invasive Invasive Invasive

  21. TYPES OF NEOPLASMS Benign Malignant Epithelial Connective tissue Lymphoid /haemopoietic Germ cell

  22. BENIGN EPITHELIAL NEOPLASMS Papilloma • squamous • transitional Adenoma • glandular

  23. MALIGNANT EPITHELIAL NEOPLASMS Carcinomas Squamous: skin Transitional: bladder Adeno: stomach, colon Basal cell: skin

  24. CONNECTIVE TISSUE NEOPLASMS Smooth muscle: Leiomyoma Fibrous tissue: Fibroma Bone: Osteoma Cartilage: Chondroma Fat: Lipoma Nerve: Neurofibroma Nerve sheath: Neurilemmoma Glial cells: Glioma

  25. CONNECTIVE TISSUE NEOPLASMS Smooth muscle: Leiomyosarcoma Bone: Osteosarcoma Fibrous tissue: Fibrosarcoma Cartilage: Chondrosarcoma Fat: Liposarcoma Nerve: Neurofibrosarcoma Nerve sheath: Neurilemmosarcoma Glial cells: Malignant glioma

  26. LYMPHOID Malignant lymphoma (B and T) Hodgkins Disease BONE MARROW Acute and chronic leukaemia

  27. GERM CELL Testis Teratoma Seminoma Ovary Dermoid Cyst

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